1. Field of the Invention
Embodiments of the present invention relate to a photo sensor. More particularly, embodiments of the present invention relate to a photo sensor with improved light sensitivity and a light emitting display including the same.
2. Description of the Related Art
An organic light emitting display is a self-emission display exhibiting improved characteristics, e.g., viewing angles, contrast, response speed, power consumption, and so forth, as compared to conventional display, e.g., a liquid crystal display (LCD).
The conventional organic light emitting display may include organic light emitting diodes (OLEDs), i.e., organic light emitting layers between anode and cathode electrodes. The organic light emitting displays may be divided into passive matrix types, i.e., the OLEDs may be coupled to each other between scan and signal lines in a matrix to form pixels, and active matrix types, i.e., the OLEDs may be controlled independently by thin film transistors (TFTs) that serve as switches.
The conventional organic light emitting display may operate by applying voltage to the anode and cathode electrodes of the OLEDs, so the organic light emitting layers may emit light in response to the voltage. The conventional OLEDs, however, may have a predetermined brightness range regardless of external light, so brightness output from the conventional organic light emitting display may be unaffected by changes in external luminance. For example, when external luminance is high, brightness output from the conventional organic light emitting display may be too low, and when external luminance is low, brightness of from the conventional organic light emitting display may be too high. As such, contrast in the conventional organic light emitting display may be reduced, so image visibility may be deteriorated. In addition, the predetermined brightness range of the OLEDs may increase power consumption of the conventional light emitting display.